In recent years, as our society has developed into a highly advanced information society, telecommunication equipment, computer systems, online service systems, automatic production line control systems and precision control systems have been increasingly distributed. In order to supply high-quality power to such sensitive and important systems, the research and development of superconducting magnetic energy storage (SMES) systems has been active. The superconducting magnetic energy storage (SMES) systems are diverse, including small-scale superconducting magnet energy storage systems for controlling power quality, and large-capacity superconducting magnet energy storage systems for load leveling. Recently, in order to control the power quality of sensitive loads, small-scale superconducting energy storage systems having a capacity on the order of a few MJ have been commercialized and effectively used for industrial and military purposes. The superconducting magnetic energy storage system has as its main component a superconducting magnet obtained by winding a thin tape-shaped superconducting wire. Because the superconducting wire contains a conducting material, it needs to be insulated before it is wound. In the prior art, a film made of insulating material was spirally wound around the outermost layer of the superconducting layer to form an insulating layer, but this film is easily torn, for example, by burs formed at the corners of the superconducting wire. Also, it makes the surface of the superconducting wire non-uniform, causes various problems, and also complicates the production process.
Meanwhile, to the central portion of the superconducting magnet obtained by winding the superconducting wire, a separate lead wire for detecting a quench or the like was connected in order to detect a voltage signal. However, the lead wire has a problem in that it forms a physical/electrical loop that generates a noise by induced electromotive force. In other words, the lead wire causes misjudgment or misoperation due to an electromagnetic noise, thus making quench detection impossible.